If you answered the Some Like it Hot actress, it might be time for you to visit an optician…

The test combines a detailed image of Einstein, and a blurry photo of Monroe, and has become the latest optical illusion to go viral since the internet became obsessed with the colour of a dress earlier this year.

Developed Dr Aude Oliva of Massachusetts Institute of Technology (MIT) in the US, this type of illusion is a called a hybrid image. It combines a low spatial frequency - or blurry - image with a high special frequency - or clear - image.

As the illusion enlarges in the video posted by Asap Science on YouTube yesterday, healthy eyes will see Einstein’s face, and ignore the blurry outline of Monroe.

However, if a person does not see the Nobel Prize winning scientist’s face, this could be an indication of vision problems.

“Depending on how well you’re able to focus, or pick up contrast, your eye will only pick out details,” the video explains.

“Up close, we’re generally able to pick up fine details like Einstein’s moustache and wrinkles. But as the distance increases, or if your vision is poor and creates a more blurred image in the first place, your ability to pick up details fades away," it adds.

Researchers at MIT have spent over a decade creating hybrid optical illusions. In a recent study, participants were shown an image of Einstein with a high spatial frequency, which is visible close up, and one of Monroe with low spatial frequencies, making it visible the further away you are.

When subjects were shown hybrid images for 30 milliseconds, they were only able to distinguish the low spatial resolution, or blurry, parts. However, when they saw the images for 150 milliseconds, they only recognised the image produced in high spatial resolution, The Times reported.

Dr Oliva claimed that this reveals that our brains discriminate between picking out fine detail in some situations, and broader detail in others.